The aim of the study is to define the optimal management of localized lesions in patients with acute leukemia and in particular to determine in a controlled fashion whether low-dose irradiation therapy administered to such sites will facilitate the healing process and prevent the development of disseminated infection. Patients are therefore randomized to receive either local care alone or local care plus megavoltage irradiation to the local lesions. Twenty-two patients have entered into this study and 11 have received radiotherapy with all lesions completely regressing by day 11. Eleven patients did not receive radiotherapy and eight had complete resolution, one partial resolution and two showed some progression. There have been nine recurrences among this group of 22 patients and 3 of these recurrences have occurred in sites previously irradiated while 6 in those not previously irradiated. It would therefore appear that localized radiotherapy may have some beneficial effects on rate of resolution and prevention of recurrences.